With the advent of a public desire for a variety of snacks and other convections, it has become somewhat common practice to combine baked dough products with fillings, either fruit or otherwise. When combining fillings with baked products, the food technology is advancing to develop processes and fillings which do not degrade the dough product and also allows efficiency in combining and baking such products. The use of fillings have often posed numerous technical difficulties related to eating quality and shelf-life when used in combination with extremely low water activity food casings or food materials where it is desirable to maintain the crispness of the casing or food material. Moisture will often migrate from the filling to portions of the food casing or casing material where moisture levels and water activities (Aw) are lower than that of the filling. This can cause undesirable changes both in the texture of the food casing and in the overall shelf-life of the finished food. To maintain the shelf-life and the desired textural properties (crisp/crunchy) of the food casing, the filling must be at an Aw equal to or below that of the food casing. As an advance in the technology, a process and a formulation is described in Jindra application Ser. No. 09/748,768), incorporated by reference herein as background information.
The formula and processing method as disclosed in Jindra, U.S. Pat. No. 6,528.104, refers to a low moisture filling with an Aw less than 0.60 (preferably less than 0.40) that is applied to or injected into a pre-baked food casing or food material. This prior method is not used where the filling is applied to or injected prior to the baking process. Consequently, most manufacturers of filled bakery items, particularly filled pretzels, inject or apply the filling only after the dough casing has been baked. This method of incorporating a low Aw filling into a previously baked dough or food casing can often result in inconsistencies related to fill levels and breakage both of which can result in substantial amounts of re-work, product loss, or consumer dissatisfaction.
Most fillings below an Aw of 0.60, and more specifically below an Aw of 0.40, can contain as little as 5% moisture. Such conditions adversely affect and even preclude the use of most stabilizers, such as starches and hydrocolloids which are commonly used to provide bake stability in higher moisture fillings (Aw>0.60) as disclosed in Rock (U.S. Pat. No. 5,932,270). Rock U.S. Pat. No. 5,932,270 is also incorporated by reference. Ingredients in the Rock patent rely on the availability of excess water to provide a means of hydration whereby functionality (i.e., bake stability) is achieved. Bake stability is generally measured in the degree of spread a filling experiences when subjected to oven conditions. The greater the degree of spread the less bake stability a filling possesses. There is general industry consensus that such ingredients cannot provide the same level of functionality in fillings whose Aw is less than 0.60 and more specifically those whose Aw is less than 0.40 for the very reason that water is unavailable for proper hydration. Therefore, it is for this reason fillings of the prescribed water activity are not considered bake stable.
Fillings with water activities less than 0.60, and more specifically less than 0.40, generally use high levels of shortening or oil to replace water. This is done not only to lower the Aw of the filling but also to provide some fluidity during processing in order to increase the ease of manufacture. The high levels of oil in such fillings presents a twofold problem in terms of bake stability. The first being that by replacing water with oil, the oil is unable to activate starches and/or hydrocolloids that might otherwise provide some level of bake stability. Second and more importantly, the oil is heat sensitive and quickly melts at slightly elevated temperatures (75 F-145 F). Generally, internal filling temperature reaches 190 F during bake. As the oven temperature rises, the oil/shortening melts and with little effort begins to leach out of the filling into the surrounding casing or food material. Depending on the degree of leaching, the effect can be detrimental to visual appeal and also the organoleptic qualities of the filling.
Therefore, it is desirable to develop a filled food product having a filling with low water activity that combines desirable organoleptic characteristics and ease of manufacture with excellent bake stability.